1. Field of the Invention
The present invention relates to a vaporized fuel treatment apparatus that is attached to a filler neck of a fuel tank for use, and adsorbs vaporized fuel from the fuel tank.
2. Description of the Related Art
To adsorb vaporized fuel generated in a fuel tank, a tank cap type canister in which activated carbon serving as an adsorbent is charged into a tank cap has been proposed (see Japanese Unexamined Patent Application Publication No. 2008-120287, for example). With this kind of tank cap type canister, vaporized fuel can be treated using a simple construction, and therefore this type of canister is often employed as a vaporized fuel treatment apparatus for a general purpose engine or the like.
The canister described in Japanese Unexamined Patent Application Publication No. 2008-120287 is structured such that the activated carbon is simply charged into the tank cap, and it is therefore difficult to cause the vaporized fuel to travel to all of the activated carbon. In other words, a vaporized fuel adsorption efficiency of the activated carbon is low, and therefore a large amount of activated carbon must be charged into a large canister in order to secure a required vaporized fuel treatment capacity.
Further, when liquid fuel seeps into the activated carbon, a vaporized fuel adsorption performance of the activated carbon deteriorates, and it is therefore important to prevent liquid fuel from seeping into the activated carbon. In particular, in a general purpose engine that serves as a power source for various instruments, the fuel tank may vibrate or tilt, and therefore a structure for preventing liquid fuel from flowing into the activated carbon is required.